I. Field of the Invention
This invention relates to a process for treating wastewater which contains an undesirable level of suspended organic materials. In a further aspect, the invention relates to a process for treating wastewater such as is obtained in connection with polymerization processes and chemical compounding.
II. Brief Description of the Prior Art
Large amounts of wastewater are generated in connection with the running of chemical plants where chemical compounding and latex polymerization processes, for example, are carried out on a daily basis. Such wastewater is loaded with suspended and dissolved organic materials including mixed polymer latex wastes also including various ionic and non-ionic surfactants at solids concentrations typically ranging from 0.05 to 5 weight percent. Based on ecological considerations, disposal of such untreated wastewater by downstream dumping or draining in leach fields is often restricted or prohibited by statute.
A variety of processes are known for the primary treatment of wastewater containing the mentioned contaminants. A representative process of the prior art comprises the precipitating and coagulating of the solids therein by chemical means and subjecting the wastewater to a step of dissolved air flotation so as to float the sludge formed of coagulated particulates to the surface. The sludge is separated from the liquid by mechanical means and is thereafter buried while the treated wastewater is disposed of by spray irrigation in slow rate land treatment or leach fields. Lime, hydrated calcium oxide, in conjunction with ferric chloride, ferric sulfate, or alum, is commonly used to precipitate and coagulate the solids. In other processes ferric chloride is used in conjunction with sodium hydroxide. None of such processes is favored in that use of the mentioned reagents adds undesirable leachable anions such as chloride or sulfate anions to the wastewater. Thus the prior art lacks an efficient treatment process containing a chemical coagulation step which does not add any undesirable anions and cations to the wastewater.
It is an object of this invention to provide a process for treating wastewater which contains an undesirable level of suspended organic materials while avoiding the addition of chloride or sulfate anions and sodium cations.
It is a further object of this invention to provide an efficient process for treating wastewater yielding high solids separation.
These and other objects will be achieved in accordance with the invention described below.